Product information "3pi+ Chassis Kit (No Motors or Electronics)"
This chassis gives you everything you need to build your own differential-drive 3pi+ robot based on you own choice of Micro Metal Gearmotors and electronics. Motors are deliberately not included with the kit so that you can pick your own to customized the performance of your robot. The kit includes the following parts:
3pi+ chassis, with integrated 4×AAA battery holder and ball caster
3pi+ bumper skirt
two 3pi+ motor clips
two 32×7 mm Pololu wheel hubs and silicone tires
four single AAA battery contacts
two double AAA battery contacts
1/2″-diameter plastic ball
The majority of the chassis is made from white ABS plastic. The 3pi+ chassis has integrated holders designed specifically for Micro Metal Gearmotors, which can then be securely held in place by snapping on the motor clips or the bumper skirt. The included wheels press-fit onto the shafts of the Micro Metal Gearmotors. The 3pi+ chassis also has an integrated rear ball caster socket that the included plastic ball pops into.